HI I have a 93 GMC 3500 with a 6.5td i just got the truck with a bad motor and just put in a rebuilt long block from ATK. The first thing im having is a howling sound coming from the drivers side sounds like from under the dash or by the hydro booster it comes on when the engine is under load and if i let off the gas it go's away and if i give it more it gets louder then when i get up to about 50mph it go's away. It dont always happen but when it does its very loud. The other thing is this engine dont have as much power as my other 6.5td could I have timed my injector pump 180 off? would the engine run with the pump 180 off? please let me know if you have any idea's thanks